import sys
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

n = I()
a = LI()
sum = 0
MOD = 998244353
s = pow(2, n-2, MOD)

if n == 1:
    print(a[0]%MOD)
else:
    for i in range(n):
        sum += a[i]*(2*s+s*i)%MOD
        sum %= MOD
    print(sum)